Identification and lipolytic activity of yeasts isolated from foods and wastes.

Thirty-three yeasts were isolated from palm oil industrial wastes and traditional fermented foods in Thailand. Based on the analysis of the sequences of the D1/D2 region of the large subunit ribosomal RNA gene (LSU rDNA) and their phenotypic characteristics, they were identified as Pichia kudriavzevii (11 isolates), Candida ethanolica (1 isolate), Clavispora lusitaniae (2 isolates), Ogataea polymorpha (1 isolate), Hanseniaspora opuntiae (1 isolate), Lodderomyces elongisporus (1 isolate), Saccharomyces cerevisiae (2 isolates), C. tropicalis (5 isolates), Yarrowia lipolytica (2 isolates), Magnusiomyces ingens (1 isolate), and Magnusiomyces capitatus (3 isolates), Trichosporon insectorum (1 isolate), and Trichosporon asteroides (2 isolates). Seven strains, T. insectorum 4E-1D, M. capitatus 5E-1T and 5E-2D, T. asteroides 8E-1T and 8E-1D, and Y. lipolytica Fy-12 and Fy-13, showed high lipolytic activity ranged from 5.21 ± 0.09 to 45.68 ± 2.37 U/mL. Moreover, these seven strains exhibited good lipolytic activity after culturing in the medium containing palm oil (11.79 ± 0.67 to 28.19 ± 4.84 U/mL) and soy oil (9.14 ± 1.08 to 22.97 ± 0.69 U/mL) as lipase inducers. The result of this study suggests that the palm oil industrial wastes and Thai fermented foods could be promised as the invaluable sources of lipolytic yeasts.

Enterococcus florum sp. nov., isolated from a cotton flower (Gossypium hirsutum L.).

A Gram-stain-positive and catalase negative coccus, designated strain Gos25-1T, isolated from a cotton flower (Gossypium hirsutum L.) collected from Khao Wong district, Kalasin province, Thailand. The taxonomic position of this strain was systematically studied based upon polyphasic taxonomic methods. The strain was facultatively anaerobic and produced l-lactic acid from glucose. The predominant cellular fatty acids were the straight-chain fatty acids C18 : 1ω9c and C16 : 0. According to 16S rRNA and phenylalanyl-tRNA synthase alpha subunit (pheS) gene sequence similarity, this strain was closely related to Enterococcus pallens NBRC 100697T, E. hermanniensis CIP 108559T, E. avium NBRC 100477T and E. raffinosus NBRC 100492T with 98.9-99.1 % and 77.0-82.0 % sequence similarities, respectively. Phylogenetic analysis indicated that strain Gos25-1T was clearly distinguished from closely related species of the genus Enterococcus. Draft genome of Gos25-1T had a size of 3.99 Mb which was contained 3788 coding sequences with in silico G+C content of 42.4 mol%. The ANIb and a digital DNA-DNA hybridisation (dDDH) values between strain Gos25-1T and the closest related species, E. pallens NBRC 100697T were 73.65 and 21.10 %, respectively. According to polyphasic characterisation, this strain represents a novel species of the genus Enterococcus, for which the name Enterococcus florum sp. nov. is proposed. The type strain is Gos25-1T (=CIP 110956T=LMG 29007T=NBRC 111461T=TISTR 2382T).

Characterization and Antibacterial Activity Against Helicobacter pylori of Lactic Acid Bacteria Isolated from Thai Fermented Rice Noodle.

A total of 32 lactic acid bacteria (LAB) were isolated from Khanom-jeen, a Thai traditional fermented rice noodle. They belonged to the genus Leuconostoc (Ln), Lactobacillus (Lb), Enterococcus (E), Lactococcus (Lc), and Weissella (W), based on their phenotypic characteristics and 16S rRNA gene sequence analyses. The strains were identified as Ln. pseudomesenteroides (group 1, two strains), Ln. citreum (group 2, three strains), Ln. lactis (group 3, three strains), Lb. paracasei subsp. tolerans (group 4, two strains), E. faecium (group 5, three strains), Lc. lactis subsp. lactis (group 6, one strain), W. confusa (group 7, six strains), Lb. fermentum (group 8, seven strains), and Lb. plantarum subsp. plantarum and Lb. pentosus (group 9, five strains). Fifteen strains exhibited the inhibitory activity against Helicobacter pylori clinical isolates by spot-on-lawn method. Lb. fermentum P43-01 resisted to bile acids showed the broad spectrum of antimicrobial activity against H. pylori strains MS83 and BK364. These antagonistic effects were associated with proteinaceous compounds which are sensitive to α-chymotrypsin and pepsin. Results indicated that production of bacteriocin-like substances of selected strain might be the significant mechanism that exerted the inhibition on H. pylori. A potential strain could be used as probiotics in alternative or adjunctive therapy for a patient suffering from H. pylori infection.

Lactobacillus ixorae sp. nov., isolated from a flower (West-Indian jasmine).

A Gram-stain-positive, lactic acid bacterium, strain Ru20-1T, was isolated from a flower (West-Indian jasmine) collected from Kalasin province, Thailand. A polyphasic approach was used to determine the taxonomic position of this strain. Studies of morphological and biochemical characteristics revealed that strain Ru20-1T belonged to the genus Lactobacillus. The strain was heterofermentative, non-spore-forming and rod-shaped. It produced dl-lactic acid. Based on 16S rRNA gene sequence similarity, this strain was closely related to Lactobacillus lindneri LMG 14528T (96.8 %), Lactobacillus sanfranciscensis NRIC 1548T (95.4 %) and Lactobacillus florum NRIC 0771T (95.2 %), respectively. In addition, the pheS gene sequence of strain Ru20-1T was closely related to those of L. sanfranciscensis NRIC 1548T (92.0 %), L. lindneri LMG 14528T (89.0 %) and L. florum NRIC 0771T(85.0 %). Phylogenetic analysis indicated that strain Ru20-1T was clearly separated from closely related species of the genus Lactobacillus. The DNA G+C content of strain Ru20-1T was 47.8 mol %. The cell-wall peptidoglycan type was l-Lys-d-Asp. The major cellular fatty acids were C18 : 1ω9c, C20 : 0, C20 : 1ω9c and summed feature 7 (unknown 18.846 and/or C19 : 1ω6c and/or C19 : 0 cyclo). On the basis of the data provided, strain Ru20-1T represents a novel species of the genus Lactobacillus, for which the name Lactobacillus ixorae sp. nov. is proposed. The type strain is Ru20-1T (=LMG 29008T=NBRC 111239T=PCU 346T=TISTR 2381T).